The dictionary defines junk food to be considered something useless, extra or not needed.

Not only are those foods extremely unhealthy, they also impact how your brain and body function.

Steven Witherly is a food scientist who has spent the last 20 years studying what makes certain foods more addictive (and tasty) than others.

According to Witherly, when you eat tasty food, there are two factors that make the experience pleasurable.

First, there is the sensation of eating the food. This includes what it tastes like (salty, sweet, etc.), what it smells like, and how it feels in your mouth.

This last quality鈥攌nown as 鈥渙rosensation鈥濃�攃an be particularly important. Food companies will spend millions of dollars to discover the most satisfying level of crunch in a potato chip.

Their scientists will test for the perfect amount of fizzle in a soda. These factors all combine to create the sensation that your brain associates with a particular food or drink.

The second factor is the actual macronutrient makeup of the food, the blend of proteins, fats, and carbohydrates that it contains.

In the case of junk food, food manufacturers are looking for a perfect combination of salt, sugar and fat that excites your brain and gets you coming back for more.

In fact, studies have shown that eating foods high in sugar and fat actually changes the chemical activity of the brain making it more dependent on such foods.

A study conducted at the University of Montreal on mice showed they suffered with withdrawal symptoms after their regular junk food diet was discontinued.

In humans, these withdrawal symptoms can lead to the inability to deal with stress, make you feel depressed and eventually cravings for more of this addictive food.

Soon you may be caught in a vicious cycle even before you know it. An imbalance of fatty acids and sugar is another reason why people who consume more junk food are at a higher risk of depression as it has a dulling effect on mental function.

The consumption of sugar is considered to be one of the three major causes of degenerative disease in Canada including obesity and type 2 diabetes.

Removing sugar from your diet is not as easy as you think, because sugar is used as an additive for preservation and to make things more palatable in most commercial foods.

There are few things in life where we have a lot of control what happens to us, but the food we put into our bodies is something that is totally within our control. Making better food choices really goes a long way in promoting overall health by reducing the risk for major chronic diseases and improving brain and body functioning.

Thing of this old English proverb: 鈥淒on鈥檛 dig your grave with your own knife and fork.鈥�